THE CORPUS PONTO-BULBARE—A HITHERTO UNDE- 
SCRIBED NUCLEAR MASS IN THE HUMAN HIND BRAIN. 
BY 
CHARLES R. ESSICK, 
Johns Hopkins Medical School. 
WITH 12 FIGURES. 
In the following paper I have described a ganglionic mass which can 
be seen overlapping the restiform body just caudal to the dorsal cochlear 
nucleus and forming a direct lateral process or extension of the ganglion 
mass of the pons. This structure was undoubtedly seen long ago by 
Clarke,’ but he considered it to be an aberrant strand from the strize 
medullares, and probably it had been seen by Arnold, who also de- 
scribed it as belonging to the strial system. The caudal tip, which is 
often prominent, has attracted the attention of various authors, and was 
particularly described by Retzius* and Henle“ under the name “ Ligula” 
and “ Ponticulus ”; none of these observers, however, followed the struct- 
ure in cross sections, and its significance was consequently overlooked. 
As far as could be learned, the following paper gives the first description 
of its whole form and for the first time demonstrates its connection with 
the ganglion mass of the pons. I have found that it is constantly present 
to a greater or less degree in all human brains and possesses definite 
characteristics which seem to me to warrant a name such as is herewith 
proposed—the corpus ponto-bulbare or ponto-bulbar body. 
An adult formalin specimen, in which the structure was especially 
prominently developed, was photographed (Fig. 1) and after mordant- 
ing in a double chrome salt solution was imbedded in celloidin and cut 
in serial sections. The alternate sections were stained by the Weigert- 
Mr. J. L. Clarke: On the Intimate Structure of the Brain. Phil. Trans. 
London, 1868. 
? Gustaf Retzius: Das Menschenhirn, Vol. I, Stockholm, 1896. 
3 J. Henle: Handbuch der Systematischen Anatomie des Menschen, Vol. III, 
Part II, Braunschweig, 1879. 
AMERICAN JOURNAL OF ANATOMY.—VOL. VII. 
